1. Field of the Invention
The invention relates to x-ray photography and somewhat more particularly to an x-ray electro-photographic recording material comprised of a film carrier layer, a photo-conductive layer predominantly composed of selenium and an electrically-conductive layer positioned between the film carrier layer and the photo-conductive layer, as well as to a method of generating an electrical charge image on such recording material.
2. Prior Art
Selenium layers applied to metallic basis are principally utilized in x-ray electro-photography. The selenium layers are electrically charged and exposed through a desired master. The charge image produced, is developed by a toner powder and is transferred to an image receiving material. The utilization of such selenium plates is known, for example, from R. M. Schaffert, Electrophotography, pages 196-198, The Focal Press, London and New York.
It can also be derived from the above-referenced Schaffert book that x-ray photo-conductivity can be increased by small additions of heavy elements, such thallium to the selenium layer. The advantage of higher x-ray absorption thereby principally gained, is, however, in turn frequently restricted by the disadvantage of a reduction in mobility of the charge carriers connected therewith.
In x-ray films, it is known to utilize a rare earth oxysulfide for sensitizing x-ray films, see V. H. Degenhart, Electromedicia, Vol. 3, (1981) pages 154-158.